A turn signal switch apparatus is provided at a driver's seat of a vehicle to be operated by an operation lever in a housing which is mounted at a steering column. The turn signal switch apparatus can turn on and off a left turn indication lamp or a right turn indication lamp by rotating the operation lever from a neutral position to a left turn indication position or a right turn indication position.
A cam surface is formed within the housing and a driving body driven by the rotation of the operation lever slides on the cam surface to guide a rotation direction of the operation lever. Further, the operation lever is latched at the left turn indication position or the right turn indication position, and the turn signal switch apparatus has a canceling mechanism which rotates a handle in an indicated direction and then rotates the handle in a reverse direction to automatically return the left turn indication position or the right turn indication position to the neutral position.
According to the related art, a turn signal is mechanically canceled by using a canceling cam as the turn signal automatic canceling mechanism. However, the canceling mechanism rotates a steering wheel at a steering angle of the steering wheel which is predefined and then automatically returns the turn signal switch when the steering wheel is released. Thus, when a driver rotates the steering wheel at the predefined angle of the steering wheel or less, the turn signal switch may not automatically return, and therefore, the driver needs to manually operate the steering wheel in order to return the steering wheel to the neutral position.
Further, when the mechanical canceling mechanism uses the canceling cam, the overall size of a canceling cam assembly needs to be changed according to an outer diameter of a steering column shaft.
The matters described as the related art have been provided only for assisting in the understanding for the background of the present disclosure and should not be considered as corresponding to the related art already known to those skilled in the art.